One hundred sixty-three sixth, seventh, and eighth grade boys (n = 72) and girls (n = 91) were given the Inventory of Parent and Peer Attachment and a 23-item self-report measure of antisocial behavior. Correlations between attachment to mother, father, and best friend and antisocial behavior showed moderate, inverse associations for the sample as a whole. Explained variance in antisocial behavior predicted by attachment to best friend was redundant with parent attachment. Both for boys and girls, attachment to father was the strongest predictor of antisocial behavior. For boys, attachment relationships with best friends were related to antisocial behavior and parent attachment. For girls, relationships with best friends were independent of other attachments and antisocial behavior. Across the 11-year through 14-year age span studied here, girls showed a positive correlation between age and aggressive antisocial behavior